Name: Johnny Ball 

Age: 74

Website: johnnyball.co.uk

Famous for: Making maths and science easy for kids on 1970s/80s telly

Bio: For ever associated with fun maths and science programmes by children of the 70s and 80s, Johnny Ball's most famous series was Think of a Number, which ran from 1978 to 1984 on BBC television. It was about science generally rather than numbers specifically, and cast Ball - previously known as a Play School presenter - in the role of a twinkling, slightly bonkers teacher.

Think of a Number produced many spin-offs - Think Again, Think! Backwards, Think! This Way and so on - all of which cemented Ball's position as Britain's favourite boffin.

His age makes him a rank outsider to win Strictly Come Dancing 2012, but Ball has dancing pedigree: his daughter, Radio 2 presenter Zoe, was a contestant in series three in 2005, finishing third. She was unlucky not to be second or even first, having recorded scores of 38/40 twice with her partner Ian Waite.

Can't remember Think of a Number? Let us jog your memory...